Adequate information on the precise molecular and biological composition of the viral strains that establish HIV infection in the human host will provide effective means of immunization against HIV infection. In an attempt to identify the transmitted founder (TF) virus and differentiate the biological properties and infectious potential of the TF virus from those of the population of the early transmitted viruses, 250 patient-derived gp120 envelope glycoproteins were cloned in pMN-K7-Luc-IRESs-NefΔgp120 to obtain chimeric viruses. Samples were obtained from eight infants who had recently become infected with HIV through mother-to-child transmission (MTCT) and two adults who acquired infection through the heterosexual route and were in the chronic stage of infection. Among the 250 clones tested, 65 chimeric viruses were infectious, and all belonged to HIV-1 subtype C. The 65 clones were analyzed for molecular features of the envelope, per-infectious-particle infectivity, coreceptor tropism, drug sensitivity, and sensitivity to broadly neutralizing antibodies. Based on genotypic and phenotypic analysis of the viral clones, we identified 10 TF viruses from the eight infants. The TF viruses were characterized by shorter V1V2 regions, a reduced number of potential N-linked glycosylation sites, and a higher infectivity titer compared to the virus variants from the adults in the chronic stage of infection. CXCR6 coreceptor usage, in addition to that of the CCR5 coreceptor, which was used by all 65 chimeric viruses, was identified in 13 viruses. The sensitivity of the TF variants to maraviroc and a standard panel of neutralizing monoclonal antibodies (VRC01, PG09, PG16, and PGT121) was found to be much lower than that of the virus variants from the adults in the chronic stage of infection.IMPORTANCE Tremendous progress has been made during the last three and half decades of HIV research, but some significant gaps continue to exist. One of the frontier areas of HIV research which has not seen a breakthrough yet is vaccine research, which is because of the enormous genetic diversity of HIV-1 and the unique infectious fitness of the virus. Among the repertoire of viral variants, the virus that establishes successful infection (transmitted founder [TF] virus) has not been well characterized yet. An insight into the salient features of the TF virus would go a long way toward helping with the design of an effective vaccine against HIV. Here we studied the biological properties of recently transmitted viruses isolated from infants who acquired infection from the mother and have come up with unique characterizations for the TF virus that establishes infection in the human host.
Current approaches do not eliminate all human immunodeficiency virus type 1 (HIV-1) maternal-to-infant transmissions (MTIT); new prevention paradigms might help avert new infections. We administered maraviroc (MVC) to rhesus macaques (RMs) to block CCR5-mediated entry, followed by repeated oral exposure of a CCR5-dependent clone of simian immunodeficiency virus (SIV) mac251 (SIVmac766). MVC significantly blocked the CCR5 coreceptor in peripheral blood mononuclear cells and tissue cells. All control animals and 60% of MVC-treated infant RMs became infected by the 6th challenge, with no significant difference between the number of exposures (P = 0.15). At the time of viral exposures, MVC plasma and tissue (including tonsil) concentrations were within the range seen in humans receiving MVC as a therapeutic. Both treated and control RMs were infected with only a single transmitted/founder variant, consistent with the dose of virus typical of HIV-1 infection. The uninfected RMs expressed the lowest levels of CCR5 on the CD4+ T cells. Ramp-up viremia was significantly delayed (P = 0.05) in the MVC-treated RMs, yet peak and postpeak viral loads were similar in treated and control RMs. In conclusion, in spite of apparent effective CCR5 blockade in infant RMs, MVC had a marginal impact on acquisition and only a minimal impact on the postinfection delay of viremia following oral SIV infection. Newly developed, more effective CCR5 blockers may have a more dramatic impact on oral SIV transmission than MVC.IMPORTANCE We have previously suggested that the very low levels of simian immunodeficiency virus (SIV) maternal-to-infant transmissions (MTIT) in African nonhuman primates that are natural hosts of SIVs are due to a low availability of target cells (CCR5+ CD4+ T cells) in the oral mucosa of the infants, rather than maternal and milk factors. To confirm this new MTIT paradigm, we performed a proof-of-concept study in which we therapeutically blocked CCR5 with maraviroc (MVC) and orally exposed MVC-treated and naive infant rhesus macaques to SIV. MVC had only a marginal effect on oral SIV transmission. However, the observation that the infant RMs that remained uninfected at the completion of the study, after 6 repeated viral challenges, had the lowest CCR5 expression on the CD4+ T cells prior to the MVC treatment appears to confirm our hypothesis, also suggesting that the partial effect of MVC is due to a limited efficacy of the drug. New, more effective CCR5 inhibitors may have a better effect in preventing SIV and HIV transmission.
Maraviroc (MVC) is a CCR5 coreceptor antagonist indicated in combination with other antiretroviral agents for the treatment of CCR5-tropic human immunodefinciency virus-1 infection. In this study, the metabolism of MVC was investigated in human liver microsomes to delineate the relative roles of CYP3A4 and CYP3A5. MVC is metabolized to five hydroxylated metabolites, all of which were biosynthesized and identified using mass and NMR spectroscopy. The sites of metabolism were the 2- and 3-positions of the 4,4-difluorocyclohexyl moiety and the methyl of the triazole moiety. Absolute configurations were ultimately ascertained by comparison to authentic standards. The biosynthesized metabolites were used for quantitative in vitro experiments in liver microsomes using cyp3cide, a selective inactivator of CYP3A4. (1S,2S)-2-OH-MVC was the main metabolite representing approximately half of the total metabolism, and CYP3A5 contributed approximately 40% to that pathway in microsomes from CYP3A5*1/*1 donors. The other four metabolites were almost exclusively metabolized by CYP3A4. (1S,2S)-2-hydroxylation also correlated to T-5 N-oxidation, a CYP3A5-specific activity. These data are consistent with clinical pharmacokinetic data wherein CYP3A5 extensive metabolizer subjects showed a modestly lower exposure to MVC.
The immunomodulatory effects of the CCR5-antagonist maraviroc might be beneficial in patients with a suboptimal immunological response, but results of different cART (combination antiretroviral therapy) intensification studies are conflicting. Therefore, we performed a 48-week placebo-controlled trial to determine the effect of maraviroc intensification on CD4+ T-cell counts and immune activation in these patients.
Double-blind, placebo-controlled, randomized trial.
Major inclusion criteria were 1. CD4+ T-cell count <350 cells/μL while at least two years on cART or CD4+ T-cell count <200 cells/μL while at least one year on cART, and 2. viral suppression for at least the previous 6 months. HIV-infected patients were randomized to add maraviroc (41 patients) or placebo (44 patients) to their cART regimen for 48 weeks. Changes in CD4+ T-cell counts (primary endpoint) and other immunological parameters were modeled using linear mixed effects models.
No significant differences for the modelled increase in CD4+ T-cell count (placebo 15.3 CD4+ T cells/μL (95% confidence interval (CI) [1.0, 29.5] versus maraviroc arm 22.9 CD4+ T cells/μL (95% CI [7.4, 38.5] p = 0.51) or alterations in the expression of markers for T-cell activation, proliferation and microbial translocation were found between the arms. However, maraviroc intensification did increase the percentage of CCR5 expressing CD4+ and CD8+ T-cells, and the plasma levels of the CCR5 ligand MIP-1β. In contrast, the percentage of ex-vivo apoptotic CD8+ and CD4+ T-cells decreased in the maraviroc arm.
Maraviroc intensification of cART did not increase CD4+ T-cell restoration or decrease immune activation as compared to placebo. However, ex-vivo T-cell apoptosis was decreased in the maraviroc arm.
Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the general population. Its severity ranges from simple steatosis to cirrhosis. C-C chemokine ligand type 5 or RANTES (Regulated upon Activation, Normal T-cell Expressed, and Secreted) plays an important role in the progression of hepatic inflammation and fibrosis. Our objective was to examine the preventive and therapeutic effects of maraviroc (MVC), a C-C chemokine receptor 5 antagonist, on liver pathology in an NAFLD mouse model. A total of 60 male C57BL/6 mice were randomly assigned to 1 of 4 groups: (1) high-fat diet (HFD) group or control group, (2) preventive group (HFD group plus MVC in drinking water since the beginning of the study), (3) early-therapeutic group (HFD group plus MVC in drinking starting at week 24 of the study), and (4) late-therapeutic group (HFD group plus MVC in drinking water starting at week 36 of the study). All mice were sacrificed at week 48. The hepatic triglyceride concentration in the HFD group was significantly higher than that in the groups treated with MVC at any time. Gene expression associated with lipogenesis (diacylglycerol acyltransferase 2 and proliferator-activated receptor-γ), insulin resistance (insulin receptor substrate-2), and β-oxidation (carnitine palmitoyltransferase 1A and acyl-CoA oxidase) was significantly reduced in all the groups treated with MVC. In summary, the beneficial effect of MVC on hepatic steatosis is maintained throughout the study.
The proportion of HIV-infected patients with overweight/obesity has increased in recent years. These patients have an increased metabolic/cardiovascular risk compared with non-obese patients. Modulation of gut microbiota composition arises as a promising tool to prevent the development of obesity and associated disorders. The aim of this study was to investigate the impacts of maraviroc (MVC), a CCR5 antagonist approved for clinical use in HIV-infected patients, on gut microbiota composition in a mouse model of obesity.
Thirty two male C57BL/6 mice were assigned to:a) Control (chow diet), b) MVC (chow diet plus 300 mg/L MVC), c) High-fat diet (HFD) or d) HFD/MVC (HFD plus 300 mg/L MVC) groups. Body weight and food intake was recorded every 2-3 days. Mice were euthanized after 16 weeks of treatment and cecal contents were removed to analyse by real-time PCR four bacterial orders from the most dominant phyla in gut.
Mice fed with a HFD showed a significant increase in Enterobacteriales (p<0.001 vs. control). MVC treatment induced a significant decrease in control (p<0.05) and HFD fed mice (p<0.001). Interestingly, this order was positively associated with body weight gain, insulin resistance and fatty liver. HFD induced a significant decrease in Bacteroidales and Clostridiales levels (p<0.05 and p<0.01, respectively). MVC decreased the presence of Bacteroidales (p<0.05 vs. control) while an increase was observed in HFD/MVC mice (p=0.01 vs. HFD). No direct effects of MVC were observed on Clostridiales and Lactobacillales.
MVC may constitute a new therapeutic option to prevent obesity and related disorders in HIV-infected patients.
To describe the pharmacokinetics of maraviroc in human immunodeficiency virus (HIV)-infected women during pregnancy and post partum.
HIV-infected pregnant women receiving maraviroc as part of clinical care had intensive steady-state 12-hour pharmacokinetic profiles performed during the third trimester and ≥2 weeks after delivery. Cord blood samples and matching maternal blood samples were taken at delivery. The data were collected in 2 studies: P1026 (United States) and PANNA (Europe). Pharmacokinetic parameters were calculated.
Eighteen women were included in the analysis. Most women (12; 67%) received 150 mg of maraviroc twice daily with a protease inhibitor, 2 (11%) received 300 mg twice daily without a protease inhibitor, and 4 (22%) had an alternative regimen. The geometric mean ratios for third-trimester versus postpartum maraviroc were 0.72 (90% confidence interval, .60-.88) for the area under the curve over a dosing interval (AUCtau) and 0.70 (0.58-0.85) for the maximum maraviroc concentration. Only 1 patient showed a trough concentration (Ctrough) below the suggested target of 50 ng/mL, both during pregnancy and post partum. The median ratio of maraviroc cord blood to maternal blood was 0.33 (range, 0.03-0.56). The viral load close to delivery was <50 copies/mL in 13 women (76%). All children were HIV negative at testing.
Overall maraviroc exposure during pregnancy was decreased, with a reduction in AUCtau and maximum concentration of about 30%. Ctrough was reduced by 15% but exceeded the minimum Ctrough target concentration. Therefore, the standard adult dose seems sufficient in pregnancy.
NCT00825929 and NCT000422890.
In this study, we have characterized quasispecies dynamics and the evolution of viral tropism in naive HIV-1-infected patients treated with a short course of maraviroc monotherapy (ClinicalTrials.gov registration no. NCT01060618) independently of the tropism of the infecting virus. We randomly selected 20 patients infected with viruses displaying different basal tropisms-10 carrying R5 and 10 carrying dual/mixed X4 (DM/X4) viruses-at recruitment as determined by phenotypic assay (Trofile). Evolution of viral quasiespecies at the end of treatment was determined by ultradeep sequencing of the V3 region using a 454 Life Sciences Platform and geno2pheno (g2p) algorithm for viral tropism prediction. The false-positive rate (FPR) that defines the probability of classifying an R5 virus falsely as X4 was set at 10%. X4-specific HIV-1 viral load (VL) was calculated from sequences with an FPR of <3.75%. Virological response as defined as >1-log10 copies/ml reduction in VL was detected in 70% of patients independently of the basal tropism of the infecting virus. Viral tropism remained stable, and nonsignificant differences in FPR values before and after treatment were found for the majority of patients in both tropism groups. Only three patients (one with R5 and two with DM/X4 viruses) showed an increased (>1 log) X4 VL, and one patient harboring a DM/X4-tropic virus displayed a significant reduction in FPR values at the end of treatment. Fast changes in the composition of viral populations were observed in all patients after 10 days of maraviroc (MVC) monotherapy treatment, and a complete replacement of viral quasiespecies was found in 3/10 patients carrying R5-using viruses and 4/10 patients carrying DM/X4-using viruses.IMPORTANCE Initiation of treatment with maraviroc requires previous determination of viral tropism by genotypic or phenotypic methods because of the risk of treatment failure and selection of DM/X4-tropic variants. In this study, we confirm previous work showing that the virologic response to maraviroc is independent of basal tropism. By deep-sequencing analysis, we determined that fast changes in viral populations were due to the emergence of minority variants in some patients whereas in others generation of new strains was detected. The risk of DM/X4 selection was very low as FPR values remained stable, and only one patient showed a detrimental switch to DM/X4 variants. Our data show that some DM/X4 viruses are sensitive to maraviroc treatment probably because only a low proportion of DM/X4 viruses use preferentially the X4 receptor and contain authentically maraviroc-resistant viruses that are not accurately detected by current assays.